OpenMapChest shows water everywhere!
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 14 years
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I've been using OSM maps for quite some time on our old Nuvi 265WT and generally find that they are more detailed and accurate than the Garmin maps but address search seems to be relatively nonexistant. Picking a favorite or previously found location works well or if you're desperate, you can always switch to the outdated Garmin map, look up the address and set the destination, then switch back to the OSM map.
This is cumbersome and has very low Wife Acceptance Factor, so I thought I'd try the OpenMapChest map. Address search seems to work well and it all looks good except... pretty much all land is shown as water. The roads go where they're supposed to but they're all over water.
Has anyone else noticed this? Is this a result of a map that has topo or some other data that this older GPS unit doesn't know about?
If anyone knows the answer to this mystery I'd love to hear it!
Regards,
- Phil
My problem with OSM was that
My problem with OSM was that if I forgot to uncheck the Garmin map or any other TOPO map I had, then routing was strange. Sometimes driving over water, roads gone, and water everywhere.
INHO it's either OSM or GARMIN maps, they don't play well together.
I never get lost, but I do explore new territory every now and then.
Map Layers cause this
My problem with OSM was that if I forgot to uncheck the Garmin map or any other TOPO map I had, then routing was strange. Sometimes driving over water, roads gone, and water everywhere.
INHO it's either OSM or GARMIN maps, they don't play well together.
The strangeness is due to "layers" of maps. If the roadmap layer is on top - all is well. If another map layer overlays it, that's when the routing gets strange looking. It has do do with routable vs. non-routable maps, and which layer is on top.
It looks like water...
I'm not 100% sure it's water but it's the same color. Can you control the terrain color when you make a map with mkgmap?
This could have something to do with sea polygon generation...
You know, I just wanted to download a map but instead I'm starting to learn the mechanics of how to make one.
This is actually pretty interesting though... so it looks like this might be related to the generation of sea polygons. Mkgmap actually has a number of options related to this, like:
-generate-sea[=ValueList] Generate sea polygons. ValueList is an optional comma separated list of values:
no-sea-sectors Disable the generation of "sea sectors" when the coastline fails to reach the tile's boundary.
land-tag=TAG=VAL Tag to use for land polygons (default natural=land).
floodblocker Enable the flood blocker that prevents a flooding of land by checking if the sea polygons contain streets (works only with multipolygon processing)
So I don't know if perhaps the map author wound up flooding the entire map for this latest build by mistake, or if our old 265W can't deal with the polygon data as it's generated for this map.
If anyone else is using OpenMapChest maps and could share their experience, I'd love to hear about it. Especially if you're using it with an old Nuvi 2xx, like we are. Inquiring minds want to know.
Cheers,
- Phil